Engine intake hydrocarbon trap system

Abstract

An air intake hydrocarbon vapor trap system for an internal combustion engine comprising a hydrocarbon-adsorptive medium, such as activated carbon, disposed in a gravitationally low point in the intake air flow passageway between the entrance to the system and the engine. The intake duct itself is configured to provide the low region for disposition of the medium. The medium is thereby fully exposed to the flow of gases through the duct and is not confined to a separate walled pit as in the prior art. The medium, for example, activated carbon, may be provided in any of several forms, such as in a pelletized bed, a rigid formed structure, or as a “sheet” or “paper.” Preferably, the medium is disposed in the engine compartment to optimally transfer heat away from it during engine shut-down.

1 . A hydrocarbon vapor trap system for an internal combustion engine having a main air intake passageway, comprising: 
 a) a first portion in continuous series with said main air intake passageway and positioned vertically lower than adjacent portions of said main air intake passageway; and    b) a vapor adsorbent medium disposed in said first portion for adsorbing hydrocarbon vapors migrating outward from said engine through said passageway when said engine is shut down; and    a spoiler attached to an upper part of said first portion within said passageway for directing said migrating hydrocarbon vapors downwards toward said adsorbent medium.    
     
     
         2 . A system in accordance with  claim 1  wherein said first portion includes the lowest point in said main air intake passageway.  
     
     
         3 . A system in accordance with  claim 1  wherein said medium includes carbon.  
     
     
         4 . A system in accordance with  claim 3  wherein said carbon is activated carbon.  
     
     
         5 . A system in accordance with  claim 3  wherein said carbon is in a divided form selected from the group consisting of granulated and pelletized.  
     
     
         6 . A system in accordance with  claim 3  wherein said carbon is formed as a rigid structure.  
     
     
         7 . A system in accordance with  claim 3  wherein said carbon is formed as a sheet.  
     
     
         8 . (canceled)  
     
     
         9 . A system in accordance with  claim 1  wherein said first portion is disposed in an engine compartment whereby heat is transferred away from said first portion during engine shut-down.  
     
     
         10 . A system in accordance with Clam  9  wherein gases within said first portion are at a temperature and said medium is at a lower temperature than said temperature of said gases.  
     
     
         11 . A system in accordance with  claim 9  wherein said first portion of said main air intake passageway includes sidewalls and a bottom wall and at least one of said walls and said bottom wall includes at least one finned heat sink projection for transferring heat way from said first portion.  
     
     
         12 . An internal combustion engine having a main engine air intake passageway disposed in an engine compartment comprising a hydrocarbon vapor trap system disposed in said passageway, said system including 
 a first portion of said main engine air intake passageway positioned vertically lower than adjacent portions of said passageway, and    a vapor adsorbent medium disposed in said first portion for adsorbing hydrocarbon vapors migrating outward from said engine through said passageway when said engine is shut down; and    a spoiler attached to an upper part of said first portion within said passageway for directing said migrating hydrocarbon vapors downwards toward said adsorbent medium.    
     
     
         13 . An engine in accordance with  claim 12  wherein said first portion is disposed in said engine compartment whereby heat is transferred away from said first portion during engine shut-down.  
     
     
         14 . (canceled)